The other answer is not 100% correct.
Per TIMATIC, the database used by airlines:
Visa required, except for Passengers with a double or multiple
entry C visa issued by a Schengen Member State valid for all Schengen Member States and valid for the period of intended stay. They are visa exempt for a maximum stay of 90 days.
So if you have a double- or multiple-entry Schengen visa, you can enter Croatia on it, even before visiting the Schengen Area
You shouldn't assume you'll receive a double/multiple-entry visa, however (unless you've received one in the past), and if you only get a single-entry visa, then a Croatian visa is required as well.